The present invention relates to systems for manipulating and conveying cans or packages of foods, such as soups, vegetables or the like, from filler and closure equipment to hydrostatic sterilizers. It additionally relates to equipment for quickly toppling containers, such as soup cans, from upright vertical orientations to laid-down horizontal orientations.
Food products that are degradable and are not to be refrigerated need to be sterilized after being canned. In other words, products, such as soups, vegetables and the like--some of which are partially blanched, some of which are cooked and some of which are cold, depending upon their recipe--are filed in the containers and the containers sealed closed. These containers can, for example, be plastic cans, plastic cups, aluminum cans or steel cans. A means for effective commercial sterilization of the sealed products is to convey them on a continuous conveyor chain through a hydrostatic sterilizer, such as those manufactured by Stork Amsterdam BV (Stork) of The Netherlands or by FMC Corporation (FMC) of San Jose, Calif. Hydrostatic sterilizers are shown in U.S. Pat. Nos. 3,286,619, 3,511,168, 3,545,985, 3,615,725, 3,619,126 and 3,986,832, for example. (These patents and all other patents or publications mentioned anywhere in this disclosure are hereby incorporated by reference in their entireties.)
Another known very recent sterilizing system is disclosed in European Application Publication Number 0.438.885.A1, which is assigned to Campbell Soup Company (Campbell Soup) of Camden, N.J. This system has a separate and novel pre-heating leg which significantly preheats the packages of different products differently as needed before they enter and am conveyed through the hydrostatic sterilizer, advantageously at the same dwell time and temperature.
These sterilizers are large pieces of equipment, generally twelve to twenty feet wide, anywhere from twenty to forty to sixty feet deep and seven to ten stories tall, and are mounted on a concrete base. The cans are carried in "sticks" (a plurality of end-to-end aligned cans) on carriers continuously conveyed in a loop-shaped path in the sterilizer tower and through the different legs of the tower. A "stick" of cans typically comprises twenty cans but this can vary depending on the can height (that is, the can length when the cans are laid down), the can or package expansion rate and the sterilizer time-temperature relationship. Fewer than twenty cans may form a stick when the cans are large, but not necessarily more than twenty when the cans are small, due to sterilizer speed providing sufficient time for loading. The sticks of cans in these carriers typically travel through a water bath leg, a heat or steam chamber leg, and a cooling section leg of the sterilizer and then are discharged. The carriers are moving continuously through the legs whether the carders are empty, fully loaded or partially loaded with cans.
In particular, in the Stork and FMC hydrostatic sterilizers there is typically first an infeed leg where the cans are conveyed upwards and into a bath of water. This water leg holds on one side thereof the bubble or steam dome, that is, the steam sterilization area. The can is in this sterilization area for about fifteen minutes, conveyed out to a water leg which holds the other side of the steam dome, and to a cooling section, that is, into cold water where cool water is sprayed on the can. The can or package spends anywhere from fifty minutes or one hour to three hours, depending on the cook time, the can diameter and the product in the can, in the hydrostatic sterilizer. The sterilizer ensures that heat penetrates the outside of the can to the center of the product in the can sufficient to raise the product core to a sterilizing temperature.
In the prior an systems the cans are filled and sealed in an upright position but are horizontal when in the sterilizer carders. Examples of known filler equipment are Campbell Soup's "E.R.& D" and the fillers available from Elmar Industries of Depew, N.Y., and from FMC; and an example of closure equipment is that available from Angelus of Los Angeles, Calif. A system is thus needed to reorient the cans and to line them up end-to-end into the "sticks." This system must form the can sticks relatively quickly since the carriers move by at a rate of approximately thirty per minute. That is, there is only about two seconds to load each stick of twenty laid down cans in each carrier. A number of systems for counting and reorienting the cans and forming them in can sticks are known. However, these systems have a number of problems as discussed below.
One prior art counting or metering system comprises a multi-pointed star rotatable about a vertical axis and having five to seven pockets for spacing and metering containers. It is available from Stork as the "Telestar Counting and Metering System." The cans enter the "star" of this system vertically. The star by its rotation counts the cans and then stops the further flow after the desired number of cans have passed through it. If a random can enters the star while the star is spinning, the can often gets caught between the pinch points of the star, that is, the high points or the lobes, and thereby damages or jams the device. Since these star devices are also subject to slippage, the star either has to be stopped sooner than desired or it does not place a full twenty cans in the stick. In other words, to prevent jamming or can denting, the star was allowed to slip, but this slippage would not guarantee a consistent feed rate.
After being counted, the cans are toppled by a toppling device onto their sides. Them are a number of known prior art toppling devices. One is a toppler belt system, which consists of two belts set ninety degrees apart from one another and disposed forty-five degrees off of the deck to thereby form an inverted "V". The chime or the base of the can which is on the chain conveyor is then intercepted by the toppler belts. Since the toppler belts are running at a faster speed than that of the infeed conveyor, the bottoms or chimes of the cans, when they hit the toppler belts, are pulled up from under the cans thereby laying the cans backwards. That is, the can bottom is pulled out from under and the top of the can lays backwards. However, if there is any liquid, such as water, broth or other moisture, on the belts or on the cans, the cans tend to slip and may not fall down. Also, if the can is dented or has a defective base or chime, it may not fall. When the cans do not fall down, the toppling system jams.
Another known toppling system is a twisting can slide and is available from FMC. With this chute system there are first and second conveyors, one spaced about a foot to a foot and a half higher than the other and with an interconnecting slide or chute. The cans are conveyed to the end of the top conveyor, shoot off of that conveyor, fall over and slide down the chute to the other conveyor. Can jams can occur because no space is formed between the cans as they fall. That is, the cans tend to topple down on one another and there is a rebounding or a backward and forward motion of the cans. In other words, the FMC system uses an angled chute down which the can travels while standing vertically in a can track. At the end of the chute is a stainless steel trough which the base of the can hits causing the can to fall forward onto its side. Since this toppling action is dependent upon gravity, there is a limit to the speed obtainable, of only about four hundred cans per minute.
After a line or stick of toppled containers has been formed, this stick is kicked or robed laterally into the bars of the traveling carder of the hydrostatic sterilizer as the carrier is conveyed past the stick, and the carriers then convey the sticks through the sterilizer. The carriers have large diameter carrier bars to accommodate different sized cans, and these carders are shaped like open-ended "C" clamps. As the carder travels about a radius the ends thereof open up and when it travels in a straight path the "C" clamp closes. The diameter of the "C" is larger than the 211 diameter can so that the carder clamp can handle not only 211 diameter cans but also 305 inch diameter cans. By having these carders able to accommodate different size cans and by rolling the cans into the carrier bars, a single size set of carrier bars can be used for different sizes of cans. This is advantageous since there are approximately two thousand stainless steel carrier bars in a sterilizer, and thus to change the carder bars each time the can sizes are changed would be time consuming and expensive.
A prior art system for kicking the can sticks into the conveyor comprises an inverted trough type system, configured similar to an upside down house gutter. As that "gutter" is pivoted it kicks the cans and rolls them into the carrier bars. The cans, however, have a tendency to stand up instead of rolling into the carrier, which can jam the machine and/or dent the cans. If a can stands up outside the carrier before the carrier squeezes it, there is a safety bar and a warning light which are activated to stop the motion of the machine, and alerting the operator to manually pull the can out and reset the machine. As can be appreciated, this slows down the operation of the sterilizer and is labor intensive.
Systems are also known for feeding sticks of cans alternatingly from opposing sides into the carder bars to increase the can throughput. The cans are divided into two lines, one to each of the two kicker troughs. One method of dividing them provides an engage and disengage stop that works off the carrier parts of the cooker or sterilizer. The stop clamps the conveyance area, the cans accumulate behind it, the stop is released and a V-shaped diverter gate changes from a single chain to two flat-top conveyors that swing side-to-side at a set rate and the cans are then fed randomly. As it swings side-to-side and cans are coming in and are being discharged from the gate, the cans would tend to be knocked onto the floor and/or to jam the machine. A spring across the joint has thus been provided in the past for these systems to keep the cans from jumping off the track. That is, a bar device extends across the conveyor guide at a height such that cans laying on their sides will pass freely under it. Those which are still standing, however, will hit the bar, tripping the device and thereby shutting the machine off, and thereby indicating that a can is not in its proper laid-down orientation. Each conveyor then feeds cans to a separate kicker trough.
Examples of other prior art systems for handling various articles are shown in U.S. Pat. Nos. 2,092,773, 3,339,702, 3,403,770, 3,403,771, 3,511,168, 3,640,375, 3,827,211, 4,693,055 and 4,771,589.
It is also important that the cans after being filled and sealed are deposited quickly into the sterilizer. The travel time from the filling area to the sterilization area can be any number of minutes depending on the length of the conveyors and the distance from the filler and closure equipment to the sterilizer. The cans typically travel some distance from the filling area--on can tracks, cables, flat-top conveyors, rubber belts and/or the like--to the hydrostatic sterilizer, which might be on the opposite side of a hundred yard long building. In other words, the filled cans may have to travel anywhere from one to five minutes to reach the hydrostatic sterilizer. When the product has been heated before being canned, the temperature of the canned product before entering the sterilizer cannot drop below a mimimum temperature, which is normally 80.degree. F. If it does, the product will not sterilize properly at the sterilizer dwell time and temperature. For example, the system may be designed for an initial 80.degree. F. temperature so that it will cook for fifty minutes at 210.degree.or 250.degree. F. If the package goes in at a lower 60.degree. temperature then the core of the product in the package will likely not be heated properly in the sterilizer to thereby kill the bacteria therein. Accordingly, the cans after filling and sealing must quickly be conveyed to the area adjacent the sterilizer, laid down into can sticks and kicked into the sterilizer carriers.
Further, the cookers when operationally mounted are typically positioned in a close environment with adjacent pipings, instrumentations, computers, utility lines and so forth; that is, space in the sterilizing facilities is limited. Thus, any changes to the sterilizing system to make it more efficient and remedy these problems in the prior art must work within this limited space. Major retrofits which would involve moving buildings, pillars, columns, steam lines, utility services, roofs, walls or I-beams, draining pipes, or actually moving the ten-story hydrostatic sterilizer on its concrete base would likely be cost prohibitive.
A system which more efficiently, dependably and quickly meters the cans and topples them forward without any can jams is accordingly needed. The known systems are unable to maintain a constant twenty cans per stick but rather only a maximum of nineteen cans has been consistently possible in the past. Higher rates through the sterilizer are also being used now, since the closure equipment is filling and closing at higher speeds and the cooking time in the sterilizer is being reduced, from sixty minutes to fifty minutes, due to controlled initial temperature (fill temperature) and the previously-mentioned separate cooker preheat leg. For example for a fifty-five minute process, a rate of 26.6 can stick carriers per minute is possible, while for a fifty minute process 29.7 to 30.0 carriers per minute rate is possible. This allows for a greater throughput and more cost effective use of the sterilizer, thereby further increasing the need for an improved can metering and toppling system.